U.S. patent number 10,301,927 [Application Number 15/153,085] was granted by the patent office on 2019-05-28 for metal sealing device.
This patent grant is currently assigned to SCHLUMBERGER TECHNOLOGY CORPORATION. The grantee listed for this patent is Schlumberger Technology Corporation. Invention is credited to Alan Sallwasser.
![](/patent/grant/10301927/US10301927-20190528-D00000.png)
![](/patent/grant/10301927/US10301927-20190528-D00001.png)
![](/patent/grant/10301927/US10301927-20190528-D00002.png)
![](/patent/grant/10301927/US10301927-20190528-D00003.png)
![](/patent/grant/10301927/US10301927-20190528-D00004.png)
![](/patent/grant/10301927/US10301927-20190528-D00005.png)
![](/patent/grant/10301927/US10301927-20190528-D00006.png)
![](/patent/grant/10301927/US10301927-20190528-D00007.png)
United States Patent |
10,301,927 |
Sallwasser |
May 28, 2019 |
Metal sealing device
Abstract
A technique includes deploying an untethered object through a
passageway of a string in a well to cause the untethered object to
travel along the passageway. The technique includes operating the
untethered object as the object travels in the passageway to expand
a metal sealing device of the untethered object to cause the object
to become caught at a downhole location.
Inventors: |
Sallwasser; Alan (Houston,
TX) |
Applicant: |
Name |
City |
State |
Country |
Type |
Schlumberger Technology Corporation |
Sugar Land |
TX |
US |
|
|
Assignee: |
SCHLUMBERGER TECHNOLOGY
CORPORATION (Sugar Land, TX)
|
Family
ID: |
57276681 |
Appl.
No.: |
15/153,085 |
Filed: |
May 12, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20160333661 A1 |
Nov 17, 2016 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
62162440 |
May 15, 2015 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B
34/14 (20130101); E21B 47/092 (20200501) |
Current International
Class: |
E21B
34/14 (20060101); E21B 47/09 (20120101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Exam Report of Australian Patent Application No. 2016203152 dated
Aug. 18, 2016, 7 pages. cited by applicant.
|
Primary Examiner: Harcourt; Brad
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims benefit of U.S. Provisional Patent
Application Ser. No. 62/162,440, filed May 15, 2015, which is
herein incorporated by reference.
Claims
What is claimed is:
1. A method comprising: deploying an untethered object through a
passageway of a string in a well to cause the untethered object to
travel along the passageway; and operating the untethered object as
the object travels in the passageway to expand a metal sealing
device of the untethered object to cause the object to become
caught at a downhole location, wherein the metal sealing device is
an expandable slotted ring comprising a plurality of axially
extending beams, and wherein each beam of the plurality of axially
extending beams remains in an elastic state during enlargement.
2. The method of claim 1, wherein operating the untethered object
comprises extending an expansion member inside the metal sealing
device to transition the metal sealing device from a first outer
diameter to a larger second outer diameter.
3. The method of claim 1, wherein operating the untethered object
comprises autonomously operating the untethered object in response
to sensing a property of an environment of the string as the object
travels through the passageway.
4. The method of claim 1, wherein operating the untethered object
comprises communicating with the untethered object from an Earth
surface of the well.
5. The method of claim 1, wherein operating the untethered object
comprises operating the untethered object in response to sensing at
least one marker in the well.
6. The method of claim 1, wherein operating the untethered object
comprises sensing a repeating pattern as the object travels along
the passageway.
7. The method of claim 1, wherein deploying the untethered object
comprises pushing the object with fluid.
8. The method of claim 1, wherein operating the untethered object
comprises operating the object to perform a downhole operation
selected from the group consisting essentially of performing a
stimulation operation, operating a downhole tool and operating a
downhole valve.
9. The method of claim 1, further comprising causing the untethered
object to travel through a plurality of seats and subsequently
causing the metal sealing device to expand to cause the untethered
object to be caught by another seat.
10. The method of claim 1, wherein operating the untethered object
comprises at least one of the following: shifting a sleeve; forming
a downhole obstruction; and operating a well tool.
11. A system usable with a well, comprising: a string comprising a
passageway; and an untethered object adapted to be deployed in the
passageway such that the object travels in the passageway, the
object comprising: a metal sealing device; an actuator; and a
controller to operate the actuator to selectively radially expand
the metal sealing device as the untethered object travels in the
passageway, wherein the metal sealing device is an expandable
slotted ring comprising a plurality of axially extending beams, and
wherein each beam of the plurality of axially extending beams
remains in an elastic state during enlargement.
12. The system of claim 11, wherein the string comprises a
plurality of seats, each of the seats being sized to catch an
object having substantially the same size, and the untethered
object is adapted to pass through at least one of the seats and
controllably expand to said same size to cause capture of the
untethered by one of the seats.
13. The system of claim 11, wherein the metal sealing device
comprises: a first pressure receiving side to circumscribe an axis
of the sealing device; a second pressure receiving side to
circumscribe the axis; first axially-extending slots in the first
pressure receiving side; and second axially-extending slots in the
second pressure receiving side, the second axially-extending slots
being offset from the first axially-extending slots to form
axially-extending beams.
14. The system of claim 13, wherein the actuator comprises a
tapered expansion member to extend inside the metal sealing device
to transition the metal sealing device downhole in the well from a
first outer diameter to a larger second outer diameter.
Description
BACKGROUND
For purposes of preparing a well for the production of oil or gas,
at least one perforating gun may be deployed into the well via a
conveyance mechanism, such as a wireline or a coiled tubing string.
The shaped charges of the perforating gun(s) are fired when the
gun(s) are appropriately positioned to perforate a casing of the
well and form perforating tunnels into the surrounding formation.
Additional operations may be performed in the well to increase the
well's permeability, such as well stimulation operations and
operations that involve hydraulic fracturing. The above-described
perforating and stimulation operations may be performed in multiple
stages of the well.
The above-described operations may be performed by actuating one or
more downhole tools. A given downhole tool may be actuated using a
wide variety of techniques, such dropping a ball into the well
sized for a seat of the tool; running another tool into the well on
a conveyance mechanism to mechanically shift or inductively
communicate with the tool to be actuated; pressurizing a control
line; and so forth.
SUMMARY
The summary is provided to introduce a selection of concepts that
are further described below in the detailed description. This
summary is not intended to identify key or essential features of
the claimed subject matter, nor is it intended to be used as an aid
in limiting the scope of the claimed subject matter.
Embodiments may take the form of a method including deploying an
untethered object through a passageway of a string in a well to
cause the untethered object to travel along the passageway, and
operating the untethered object as the object travels in the
passageway to expand a metal sealing device of the untethered
object to cause the object to become caught at a downhole
location.
Other embodiments may take the form of a system usable with a well
having: a string with a passageway, and an untethered object
adapted to be deployed in the passageway such that the object
travels in the passageway. The object includes a metal sealing
device, an actuator, and a controller to operate the actuator to
selectively radially expand the metal seal as the untethered object
travels in the passageway.
Further other embodiments may take the form of an apparatus having
a metal seal. The metal seal includes a first pressure receiving
side to circumscribe an axis of the seal, a second pressure
receiving side to circumscribe the axis, first axially-extending
slots in the first pressure receiving side, second
axially-extending slots in the second pressure receiving side, and
an expansion member to extend inside the metal seal to transition
the metal seal downhole in the well from a first outer diameter to
a larger second outer diameter. The second axially-extending slots
are offset from the first axially-extending slots to form
axially-extending beams.
Advantages and other features will become apparent from the
following drawings, description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a well according to an example
implementation.
FIG. 2A is a schematic diagram of a dart in a radially contracted
state according to an example implementation.
FIG. 2B is a schematic diagram of the dart in a radially expanded
state according to an example implementation.
FIG. 3 is a flow diagram depicting a technique to use a metal
sealing device to perform a downhole operation according to an
example implementation.
FIG. 4A is a perspective view of a metal sealing device according
to an example implementation.
FIG. 4B is a perspective view of a section of the metal sealing
device showing a more detailed view of slots of the sealing device
according to an example implementation.
FIGS. 5A and 5B are perspective views of a dart illustrating radial
expansion of a metal sealing device of the dart according to an
example implementation.
FIGS. 6A and 6B are cross-sectional views of a dart illustrating
radial expansion of a metal sealing device of the dart according to
a further example implementation.
FIG. 7 is a partial cross-sectional view illustrating the metal
sealing device being caught by a downhole seat according to an
example implementation.
DETAILED DESCRIPTION
In general, systems and techniques are disclosed herein for
purposes of deploying an untethered object into a well, and
selectively expanding a metal sealing device of the untethered
object for purposes of performing a downhole operation. In this
context, an "untethered object" refers to an object that travels at
least some distance in a well passageway without being attached to
a conveyance mechanism (a slickline, wireline, coiled tubing
string, and so forth). As specific examples, the untethered object
may be a dart, a ball or a bar. However, the untethered object may
take on different forms, in accordance with further
implementations. In accordance with some implementations, the
untethered object may be pumped into the well (i.e., pushed into
the well with fluid), although pumping may not be employed to move
the object in the well, in accordance with further
implementations.
In general, the untethered object may be used to perform a downhole
operation that may or may not involve actuation of a downhole tool
As just a few examples, the downhole operation may be a stimulation
operation (a fracturing operation or an acidizing operation as
examples); an operation performed by a downhole tool (the operation
of a downhole valve, the operation of a single shot tool, or the
operation of a perforating gun, as examples); the formation of a
downhole obstruction; or the diversion of fluid (the diversion of
fracturing fluid into a surrounding formation, for example).
Moreover, in accordance with example implementations, a single
untethered object may be used to perform multiple downhole
operations in multiple zones, or stages, of the well, as further
disclosed herein.
In accordance with example implementations, the untethered object
is deployed in a passageway (a tubing string passageway, for
example) of the well, travels to a targeted position of the well
and then radially expands its metal seal to initiate a downhole
operation. In this manner, the untethered object is initially
radially contracted when the object is deployed into the
passageway. The object travels through the passageway in its
radially contracted state until reaching a predetermined location
at which the metal seal of the object radially expands. The
increased cross-section of the object due to radial expansion of
the metal seal may be used to effect any of a number of downhole
operations, such as shifting a valve, forming a fluid obstruction,
actuating a tool, and so forth. Moreover, because the object
remains radially contracted before reaching the predetermined
location, the object may pass through downhole restrictions (valve
seats, for example) that may otherwise "catch" the object, thereby
allowing the object to be used in, for example, multiple stage
applications in which the object is used in conjunction with seats
of the same size so that the object selects which seat catches the
object.
In accordance with example implementations, the untethered object
may be controlled in response to markers that are installed along a
tubular string through which the object passes. In this regard, the
untethered object may pass through a number of seats (for example),
and when the untethered object senses a marker in proximity to a
targeted seat, the untethered object radially expands as a metal
seal for purposes of causing the object to be caught by the
targeted seat. As an example, the marker may be a radio frequency
identification (RFID) tag.
In general, the untethered object is constructed to sense its
downhole position as it travels in the well and autonomously
respond based on this sensing. As disclosed herein, the untethered
object may sense its position based on features of the string,
markers, formation characteristics, sensed chemicals, mechanical
contact with features of the surrounding string, and so forth,
depending on the particular implementation. As a more specific
example, for purposes of sensing its downhole location, the
untethered object may be constructed to, during its travel, sense
specific points in the well, called "markers" herein. Moreover, as
disclosed herein, the untethered object may be constructed to
detect the markers by sensing a property of the environment
surrounding the object (a physical property of the string or
formation, as examples). The markers may be dedicated tags or
materials installed in the well for location sensing by the object
or may be formed from features (sleeve valves, casing valves,
casing collars, and so forth) of the well, which are primarily
associated with downhole functions, other than location sensing.
Moreover, as disclosed herein, in accordance with example
implementations, the untethered object may be constructed to sense
its location in other and/or different ways that do not involve
sensing a physical property of its environment, such as, for
example, sensing a pressure for purposes of identifying valves or
other downhole features that the object traverses during its
travel.
In general, the untethered object may, in accordance with example
implementations, initiate its radially expansion to cause the
object to be caught at a downhole location in accordance with any
of the ways described in U.S. Pat. No. 8,276,674, entitled,
"DEPLOYING AN UNTETHERED OBJECT IN A PASSAGEWAY OF A WELL," which
granted on Oct. 2, 2012, is hereby incorporated by reference; and
U.S. Patent Application Publication No. US 2014/0076542, entitled,
"AUTONOMOUS UNTETHERED WELL OBJECT," which published on Mar. 20,
2014 and is also hereby incorporated by reference in its
entirety.
Referring to FIG. 1, as a more specific example, in accordance with
some implementations, a multiple stage well 90 includes a wellbore
120, which traverses one or more formations (hydrocarbon bearing
formations, for example). As a more specific example, the wellbore
120 may be lined, or supported, by a tubing string 130, as depicted
in FIG. 1. The tubing string 130 may be cemented to the wellbore
120 (such wellbores typically are referred to as "cased hole"
wellbores); or the tubing string 130 may be secured to the
formation by packers (such wellbores typically are referred to as
"open hole" wellbores). In general, the wellbore 120 extends
through one or multiple zones, or stages 170 (four stages 170-1,
170-2, 170-3 and 170-4, being depicted as examples in FIG. 1) of
the well 90.
It is noted that although FIG. 1 depicts a laterally extending
wellbore 120, the systems and techniques that are disclosed herein
may likewise be applied to vertical wellbores. In accordance with
example implementations, the well 90 may contain multiple
wellbores, which contain tubing strings that are similar to the
illustrated tubing string 130. Moreover, depending on the
particular implementation, the well 90 may be an injection well or
a production well. Thus, many variations are contemplated, which
are within the scope of the appended claims.
In general, the downhole operations may be multiple stage
operations that may be sequentially performed in the stages 170 in
a particular direction (in a direction from the toe end of the
wellbore 120 to the heel end of the wellbore 120, for example) or
may be performed in no particular direction or sequence, depending
on the implementation.
Although not depicted in FIG. 1, fluid communication with the
surrounding reservoir may be enhanced in one or more of the stages
170 through, for example, abrasive jetting operations, perforating
operations, and so forth.
In accordance with example implementations, the well 90 of FIG. 1
includes downhole tools 152 (tools 152-1, 152-2, 152-3 and 152-4,
being depicted in FIG. 1 as examples) that are located in the
respective stages 170. The tool 152 may be any of a variety of
downhole tools, such as a valve (a circulation valve, a casing
valve, a sleeve valve, and so forth), a seat assembly, a check
valve, a plug assembly, and so forth, depending on the particular
implementation. Moreover, the tool 152 may be different tools (a
mixture of casing valves, plug assemblies, check valves, and so
forth, for example). As depicted in FIG. 1, the tools 152 may be
part of the tubing string 130.
It is noted that the well 90 may have more or fewer than four
stages 170, and the well 90 may have more or fewer or than four
downhole tools 152, depending on the particular implementation.
Moreover, multiple downhole tools 152 may be disposed in a given
stage 170, in accordance with example implementations.
In accordance with example implementations, a given tool 152 may be
selectively actuated by deploying an untethered object through the
central passageway of the tubing string 130. In general, the
untethered object has a radially contracted state to permit the
object to pass relatively freely through the central passageway of
the tubing string 130 (and thus, through tools of the string 130),
and the object has a radially expanded state, which causes the
object to land in, or, be "caught" by, a selected one of the tools
152 or otherwise secured at a selected downhole location, in
general, for purposes of performing a given downhole operation. For
example, a given downhole tool 152 may catch the untethered object
for purposes of forming a downhole obstruction to divert fluid
(divert fluid in a fracturing or other stimulation operation, for
example); pressurize a given stage 170; shift a sleeve of the tool
152; actuate the tool 152; install a check valve (part of the
object) in the tool 152; and so forth, depending on the particular
implementation.
For the specific example of FIG. 1, the untethered object is a dart
100, which, as depicted in FIG. 1, may be deployed (as an example)
from the Earth surface E into the tubing string 130 and propagate
along the central passageway of the string 130 until the dart 100
senses proximity of the targeted tool 152 (as further disclosed
herein), radially expands and engages the tool 152. It is noted
that the dart 100 may be deployed from a location other than the
Earth surface E, in accordance with further implementations. For
example, the dart 100 may be released by a downhole tool. As
another example, the dart 100 may be run downhole on a conveyance
mechanism and then released downhole to travel further downhole
untethered.
In accordance with an example implementation, the tools 152 may be
sleeve valves that may be initially closed when run into the well
90 but subsequently shifted open when engaged by the dart 100 for
purposes for performing fracturing operations from the heel to the
toe of the wellbore 120 (for the example stages 170-1, 170-2, 170-3
and 170-4 depicted in FIG. 1). In this manner, for this example,
before being deployed into the wellbore 120, the dart 100 may be
configured, or programmed, to sequentially target the tools 152 of
the stages 170-1, 170-2, 170-3 and 170-4 in the order in which the
dart 100 encounters the tools 152.
Continuing the example, the dart 100 is released into the central
passageway of the tubing string 130 from the Earth surface E,
travels downhole in the tubing string 130, and when the dart 100
senses proximity of the tool 152 of the stage 170-1 along the
dart's path, the dart 100 radially expands to engage a dart
catching seat of the tool 152. Using the resulting fluid barrier,
or obstruction, that is created by the dart 100 landing in the tool
152, fluid pressure may be applied uphole of the dart 100 (by
pumping fluid into the tubing string 130, for example) for purposes
of creating a force to shift the sleeve of the tool 152 (a sleeve
valve, for this example) to open radial fracture ports of the tool
152 with the surrounding formation in the stage 170-1.
In accordance with example implementations, the dart 100 may be
constructed to subsequently radially contract to release itself
from the tool 152 (as further disclosed herein) of the stage 170-1,
travel further downhole through the tubing string 130, radially
expand in response to sensing proximity of the tool 152 of the
stage 170-2, and land in the tool of the stage 170-2 to create
another fluid obstruction. Using this fluid obstruction, the
portion of the tubing string 130 uphole of the dart 100 may be
pressurized for purposes of fracturing the stage 170-1 and shifting
the sleeve valve of the stage 170-2 open. Thus, the above-described
process repeats in the heel-to-toe fracturing, in accordance with
an example implementation, as the fracturing proceeds downhole
until the stage 170-4 is fractured. It is noted that although FIG.
1 depicts four stages 170-1, 170-2, 170-3 and 170-4, the
heel-to-toe fracturing may be performed in fewer or more than four
stages, in accordance with further implementations.
In accordance with further example implementations, the dart 100
may not be constructed to radially contract after the dart 100
radially expands and becomes lands in a given downhole tool. For
these example implementations, the dart 100 may be removed through
a milling operation or the dart 100 may be constructed from one or
more degradable materials (as further described below), which
effects a timed release of the dart to eventually clear the
passageway of the tubing string 130 to allow another dart 100
(targeting another tool) to be deployed downhole or any other
operation to be performed, which relies on the passageway being
cleared.
Although examples are disclosed herein in which the dart 100 is
constructed to radially expand at the appropriate time so that a
tool 152 of the string 130 catches the dart 100, in accordance with
other implementations disclosed herein, the dart 100 may be
constructed to secure itself to an arbitrary position of the string
130, which is not part of a tool 152. Thus, many variations are
contemplated, which are within the scope of the appended
claims.
For the example that is depicted in FIG. 1, the dart 100 is
deployed in the tubing string 130 from the Earth surface E for
purposes of engaging one of the tools 152 (i.e., for purposes of
engaging a "targeted tool 152"). In accordance with example
implementations, the dart 100 autonomously senses its downhole
position, remains radially contracted to pass through tool(s) 152
(if any) uphole of the targeted tool 152, and radially expands
before reaching the targeted tool 152. In accordance with some
implementations, the dart 100 senses its downhole position by
sensing the presence of markers 160 which may be distributed along
the tubing string 130.
For the specific example of FIG. 1, each stage 170 contains a
marker 160, and each marker 160 is embedded in a different tool
152. The marker 160 may be a specific material, a specific downhole
feature, a specific physical property, a radio frequency (RF)
identification (RFID), tag, and so forth, depending on the
particular implementation.
It is noted that each stage 170 may contain multiple markers 160; a
given stage 170 may not contain any markers 160; the markers 160
may be deployed along the tubing string 130 at positions that do
not coincide with given tools 152; the markers 160 may not be
evenly/regularly distributed as depicted in FIG. 1; and so forth,
depending on the particular implementation. Moreover, although FIG.
1 depicts the markers 160 as being deployed in the tools 152, the
markers 160 may be deployed at defined distances with respect to
the tools 152, depending on the particular implementation. For
example, the markers 160 may be deployed between or at intermediate
positions between respective tools 152, in accordance with further
implementations. Thus, many variations are contemplated, which are
within the scope of the appended claims.
In accordance with an example implementation, a given marker 160
may be a magnetic material-based marker, which may be formed, for
example, by a ferromagnetic material that is embedded in or
attached to the tubing string 130, embedded in or attached to a
given tool housing, and so forth. By sensing the markers 160, the
dart 100 may determine its downhole position and selectively
radially expand accordingly. As further disclosed herein, in
accordance with an example implementation, the dart 100 may
maintain a count of detected markers. In this manner, the dart 100
may sense and log when the dart 100 passes a marker 160 such that
the dart 100 may determine its downhole position based on the
marker count.
Thus, the dart 100 may increment (as an example) a marker counter
(an electronics-based counter, for example) as the dart 100
traverses the markers 160 in its travel through the tubing string
130; and when the dart 100 determines that a given number of
markers 160 have been detected (via a threshold count that is
programmed into the dart 100, for example), the dart 100 radially
expands.
For example, the dart 100 may be launched into the well 90 for
purposes of being caught in the tool 152-3. Therefore, given the
example arrangement of FIG. 1, the dart 100 may be programmed at
the Earth surface E to count two markers 160 (i.e., the markers 160
of the tools 152-1 and 152-2) before radially expanding. The dart
100 passes through the tools 152-1 and 152-2 in its radially
contracted state; increments its marker counter twice due to the
detection of the markers 152-1 and 152-2; and in response to its
marker counter indicating a "2," the dart 100 radially expands so
that the dart 100 has a cross-sectional size that causes the dart
100 to be "caught" by the tool 152-3.
Referring to FIG. 2A, in accordance with an example implementation,
the dart 100 includes a body 204 having a section 200, whose
cross-sectional dimension D1 is controlled by a slotted metal
sealing device 210, which may surround the periphery of the body
204. The dart 100 is constructed to radially expand the metal
sealing device 210 to a radially larger cross-sectional diameter D2
(as depicted in FIG. 2B) for purposes of causing the dart 100 to
become lodged at a targeted downhole location (a seat, a tool or a
tubing location, for example).
As depicted in FIG. 2A, in accordance with an example
implementations, the dart 100 may includes a controller 224 (a
microcontroller, microprocessor, field programmable gate array
(FPGA), or central processing unit (CPU), as examples), which
receives either commands from the surface or feedback as to the
dart's position and generates the appropriate signal(s) to activate
an actuator 220 at the appropriate time to cause radial expansion
of the metal sealing device 210.
As depicted in FIG. 2A, among its other components, the dart 100
may have a stored energy source, such as a battery 240; a sensor
230 to sense one or more downhole parameters; and an interface (a
wireless interface, for example), which is not shown in FIG. 2A,
for purposes of programming the dart 100 with one or more
parameters (a threshold marker count or other information to inform
the controller 224 when to radially expand the metal sealing device
210, for example) before the dart 100 is deployed in the well
90.
Thus, referring to FIG. 3, a technique 300 in accordance with
example implementations includes deploying (block 304) an
untethered object in a passageway of a string to allow the object
to travel through the passageway. Pursuant to the technique 300,
the untethered object operated (block 308) to expand a metal
sealing device of the object downhole during travel of the object
to perform a downhole operation.
Referring to FIG. 4A, in accordance with example implementations,
an untethered object, such as a dart, may include a metal sealing
device 400 for purposes of forming an annular seal between the
exterior of the object and a downhole seat. In general, the metal
sealing device 400 is an expandable slotted ring having a radially
contracted position and a radially expanded position. As described
herein, the metal sealing device 400 circumscribes an axis 401, and
the metal sealing device 400 may be moved upon a conical expansion
member by an actuator of the untethered object (such as actuator
220 (FIG. 2A), as controlled by controller 224) for purposes of
controlling the expansion of the metal sealing device 400.
The outer diameter of the metal sealing device 210 establishes the
outer diameter for the untethered object. In its radially
contracted position, outer diameter of the metal sealing device 400
is sufficiently small enough to allow the untethered object to pass
through downhole seats, tools, tubing passageways, and so forth, as
the object travels downhole. In its radially expanded position,
outer diameter of the metal sealing device 400 is sufficiently
large to cause the untethered object to become lodged, or caught,
by a targeted seat, downhole tubing diameter, downhole tool or
other restriction, which has an appropriately sized inner
diameter.
More specifically, in accordance with example implementations, the
metal sealing device 400 is constructed to expand to its radially
expanded state for purposes of causing the untethered object to be
received, or caught, by a targeted downhole seat. When caught by
the seat, the metal sealing device 400 forms an annular fluid seal
between the outside surface of the untethered object's body and the
seat, so that a corresponding fluid barrier, or obstruction, is
formed. As depicted in FIG. 4A, the metal sealing device 400 forms
a ring about the longitudinal axis 401 and extends from an inner
radius R1 to an outer radius R2. The R1 and R2 radii slightly
expand, as the metal sealing device 400 transitions between from
its radially contracted state to its radially expanded state, in
accordance with example implementations.
In accordance with example implementations, the ability of the
metal sealing device 400 to form a fluid seal (an absolute seal or
a seal that at least is associated with a sufficiently small
leakage flow to allow sufficient pressurization of the string above
the untethered object, for example) is due to one or more of the
following characteristics. First, the area of communication between
a relatively high pressure side 408 and a relatively low pressure
side 404 of the metal sealing device 400 is small, such as less
than one percent of the otherwise open area in the absence of the
metal sealing device 400, in accordance with example
implementations. Secondly, the metal sealing device 400, in
accordance with example implementations, has slots on the high 408
and low 406 pressure sides that operate in a complementary fashion
to deform the device 400 in a manner that enhances the fluid
seal.
More specifically, referring to FIG. 4B (a more detailed view of
the metal sealing device 400) in conjunction with FIG. 4A, in
accordance with example implementations, the metal sealing device
400 has slots 410 on the low pressure side 404 and slots 414 on the
high pressure side 408. Each slot 410 on the low pressure side 404
radially extends from the inner radius R1 to the outer radius R2 of
the metal sealing device 400; and each slot 410 extends axially
from the low pressure side 404 toward the high pressure side 408,
stopping short of extending through the high pressure side 408. The
slots 410 are distributed around the periphery of the low pressure
side 404, as depicted in FIG. 4A. Each slot 414 on the high
pressure side 408 radially extends from the inner radius R1 to the
outer radius R2 of the metal sealing device 400; and each slot 414
extends axially from the high pressure side 408 toward the low
pressure side 404, stopping short of extending through the low
pressure side 404. The slots 414 are distributed around the
periphery of the high pressure side 408, as depicted in FIG.
4A.
As depicted in FIGS. 4A and 4B, the slots 410 are peripherally
offset with respect to the slots 414 to create corresponding
axially-extending beams 421 of the metal sealing device 400. With
an increasing pressure, the open area of the communication path
decreases because the beams 421 have a measure of plasticity in the
radial direction, allowing deformation of the metal sealing device
400 further into the communication path. Referring to FIG. 4B, the
pressure force on the high pressure side 408 tends to open the
slots 414 (as illustrated by gap G2), with resultant consequence of
closing the slots 410 on the low pressure side 408 (as illustrated
by gap G1), further blocking fluid communication.
In accordance with example implementations, each of the beams 421
remains in an elastic state during enlargement. In doing so, during
the expansion process, the slots 414 on the high pressure side 408
open by substantially equal amounts. Otherwise, there would be a
preferential yielding at one of the slots 414, which may otherwise
result in breaking of a beam 421; or otherwise result in a given
slot 414 become too large to form a proper seal. When mated with a
seat, in accordance with example implementations, the seat subtends
the entirety of the metal sealing device 400, thereby blocking
fluid communication between the axially-extending slots 414 on the
high pressure side and the axially-extending slots 410 on the low
pressure side.
In accordance with example implementations, the metal sealing
device 400 may be formed from any suitable degradable metal or
metal alloy. For example, the metal sealing device 400 may be
formed from one or more of the following metals/metal alloys: a
basic metal such as aluminum, gallium, indium, tin, thallium, and
lead; an alkali metal such as magnesium, calcium and strontium. As
an example, the metal sealing device may include an aluminum
gallium alloy. For example, the composition may include
approximately 80 percent or more by weight of aluminum or an
aluminum alloy and approximately or greater than two percent of a
select material or materials such as gallium, indium, tin, bismuth,
and lead. As an example, a select material or materials may include
one or more basic metals where, for example, basic metals include
gallium, indium, tim, thallium, lead and bismuth (e.g., basic
metals of atomic number 31 or greater).
Moreover, in accordance with example embodiments, the slots 410 and
414 may be formed in the metal sealing device in accordance with
any suitable process. For example, the slots 410 and 414 may be
formed in the metal sealing device using one or more of the
following processes: mechanical processes such as drilling,
cutting, grinding and so forth; laser cutting, water jet cutting;
plasma cutting; and so forth. The cutting process may be precision
controlled by a computer numerical controlled systems or any other
suitable computer controlled system.
FIGS. 5A and 5B depict expansion of the metal sealing device 400
when used on the dart 100, in accordance with example
implementations. In particular, FIG. 5A depicts the metal sealing
device 400 in its radially contracted state, and FIG. 5B depicts
the metal sealing device 400 in its radially expanded state.
Referring to FIG. 5A in conjunction with FIG. 4A, in accordance
with example implementations, the dart 100 has an anvil 518 that
has a conical surface 550 circumscribes the longitudinal axis 401
of the metal sealing device 400. For the radially retracted state
of the metal sealing device 400, the smaller outer diameter portion
of the conical surface 550 extends into the interior of the metal
sealing device 400 from the high pressure side 408 of the device
400, and the larger outer diameter portion of the conical surface
550 remains outside of the interior of the metal sealing device
400, as depicted in FIG. 5A. On its low pressure side 410,
engagement tabs 430 of the metal sealing device 400 extend into
corresponding recesses 510 on an actuating member 504 of the dart
100 to prevent the metal sealing device 400 from rotating about the
axis 401.
Referring to FIG. 5B in conjunction with FIG. 4A, to radially
expand the metal sealing device 400, the actuator of the dart moves
the actuating member 504 to push the metal sealing device 400
farther onto the conical surface 550 so that the larger outer
diameter portion of the surface 550 radially expands the device
400. As depicted in FIG. 5B engagement tabs 420 on the high
pressure side 414 of the metal sealing device 400 are received in
corresponding recesses 520 of the anvil 518.
FIGS. 6A and 6B depict cross-sectional views of a dart 600 that has
the metal sealing device 400, in accordance with further example
implementations. FIG. 6A depicts the metal sealing device 400 in
its radially contracted state, and FIG. 6B depicts the metal
sealing device 400 in its radially expanded state. Similar
reference numerals are used in FIGS. 6A and 6B to depict similar
components that are described above, with other reference numerals
being used to denote new/different components.
Referring to FIG. 6A, the dart 600 includes an actuating member
assembly to move the metal sealing device 400 upon the conical
surface 550 of the anvil 518 to radially expand the device 400. The
actuating member assembly includes a bullnose-shaped ring 612 and
an operator mandrel 610. The ring 612 may form the front end (the
end leading into the well) of the dart 600, and the ring 612 has an
annularly extending shoulder 615 that abuts the low pressure side
408 of the metal sealing device 400, in accordance with example
implementations. The ring circumscribes the longitudinal axis 401
and is attached to one end of the mandrel 610. The mandrel 610
circumscribes the longitudinal axis 401.
When the metal sealing device 400 is be radially expanded, an
actuator (not shown) of the dart 600 move the mandrel 610 in an
activation direction 670 to move the metal sealing device 400 upon
the larger outer diameter portion of the conical surface 550. As
depicted in FIG. 6B, the axial translational movement of the
operator mandrel 610 and the metal sealing device 400 ends when the
ring 612 abuts a far end stop 630 of the anvil 518. At this point,
the metal sealing ring 400 is axially compressed between the
shoulder 615 of the ring 612 and an annularly extending shoulder
628 of the anvil 518.
FIG. 7 is an illustration of a resulting fluid seal (i.e., fluid
barrier) that is formed between the dart 600 and a downhole seat
714, in accordance with example implementations. It is noted that
FIG. 7 merely depicts a partial cross-sectional view of the anvil
518 of the dart 600 and the seat 700 about the longitudinal axis
401, as one of ordinary skill in the art would understand that the
full cross-sectional view would contain a mirrored image about the
axis 401. As depicted in FIG. 7, the seat 714 may be formed in a
downhole member 710, such as a member of a tool, seat assembly, and
so forth. As also depicted in FIG. 7, the metal sealing device 400
may, in its final, radially expanded position, may reside in a
recessed area 720 of the conical surface 720 for purposes of
locking the sealing device 400 in its set position.
As noted above, depending on the particular implementation, the
metal sealing device 400 may or may not be retractable. For
implementations in which the metal sealing device 400 is not
retractable, the dart may be removed using a milling operation. In
further example implementations, one or more components of the
dart, such as the metal sealing ring 400 may be constructed from a
degradable material to allow removal of the device 400. In this
manner, the meal sealing ring 400 and/or one or more parts of the
dart (or other untethered object) may be constructed from
dissolving, or degradable, materials that have sufficiently fast
dissolution rates. In this manner, the dissolution rates allow
removal of the fluid barrier in a relatively short time frame, such
as a time frame of several days or several weeks, so that the well
passageway is cleared for additional operations. The parts may be,
for example, metallic parts that are constructed from dissolvable
alloys, and the dissolution rates of the parts may depend on the
formulation of the alloys. As an example, dissolvable, or
degradable, alloys may be used similar to the alloys that are
disclosed in the following patents, which have an assignee in
common with the present application and are hereby incorporated by
reference: U.S. Pat. No. 7,775,279, entitled, "DEBRIS-FREE
PERFORATING APPARATUS AND TECHNIQUE," which issued on Aug. 17,
2010; and U.S. Pat. No. 8,211,247, entitled, "DEGRADABLE
COMPOSITIONS, APPARATUS COMPOSITIONS COMPRISING SAME, AND METHOD OF
USE," which issued on Jul. 3, 2012.
Other implementations are contemplated, which are within the scope
of the appended claims. For example, in accordance with further
example implementations, a metal sealing device may be used with a
downhole tool other than an untethered object to form a downhole
fluid seal or fluid barrier in a well. In this manner, the metal
sealing device may be used with a conveyance line-tethered device,
such as a measurement tool, perforating gun, valve, and so forth,
as can be appreciated by one of ordinary skill in the art. As
another example, the metal sealing device may be used to seal
downhole completion equipment. As another example, the metal
sealing device may be used outside of the oil and gas industry,
where relatively low leak rates are acceptable.
While a limited number of examples have been disclosed herein,
those skilled in the art, having the benefit of this disclosure,
will appreciate numerous modifications and variations therefrom. It
is intended that the appended claims cover all such modifications
and variations.
* * * * *